Abstract
The TNT equivalence of an explosive is given as the equivalent mass of TNT required to produce a blast wave of equal magnitude to that produced by a unit weight of the explosive in question. Currently, there is a lack of agreement in the literature on the TNT equivalence (TNTeq) of PE4. This paper presents a combined numerical and experimental investigation of TNTeq for hemispherical PE4 charges in far-field blast events. Experimental results are compared to a series of numerical analyses conducted with different masses of TNT explosive and conclusions are drawn in order to provide a more informed value of TNTeq. It is found that a TNTeq of 1.2 best describes the blast waves produced from PE4 detonations, and this factor is found to be invariant of the distance from the explosive when considering far-field events.Keywords:
blast loading, experiment, finite element analysis, TNT equivalence.References
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[2] US Department of Defence. Structures to resist the effects of accidental explosions. US DoD, Washington DC, USA, UFC-3-340-02, 2008.
[3] C. N. Kingery and G. Bulmash. Airblast parameters from TNT spherical air burst and hemispherical surface burst. Technical Report ARBRL-TR-02555, U.S Army BRL, Aberdeen Proving Ground, MD, USA, 1984.
[4] S.A. Formby and R.K. Wharton. Blast characteristics and TNT equivalence values for some commercial explosives detonated at ground level. Journal of Hazardous Materials, 50(2-3):183–198, 1996.
[5] I. Sochet, D. Gardebas, S. Calderara, YMarchal, and B. Longuet. Blast wave parameters for spherical explosives detonation in free air. Open Journal of Safety Science and Technology, 10:31–42, 2011.
[6] P. W. Cooper. Comments on TNT Equivalence. In 20th International Pyrotechnics Seminar, pages 1–26. Colorado Springs, CO, USA, 1994.
[7] M. M. Swisdak. Explosion effects and properties. Part I – explosion effects in air. Technical Report NSWC/WOL/TR 75-116, Naval Surface Weapons Center, MD, USA, 1975.
[8] P. M. Locking. The trouble with TNT equivalence. In 26th International Symposium on Ballistics. Miami, FL, USA, 2011.
[9] K. Ackland, H. Bornstein, and D. Lamos. An analysis of TNT equivalencies using AUTODYN. Journal of Explosion Engineering, 1(3):71, 2012.
[10] J. Pachman, R. Maty´aˇs, and M. K¨unzel. Study of TATP: blast characteristics and TNT equivalency of small charges. Shock Waves, 24(4):439–445, 2014.
[11] ABAQUS, v.6.13. Documentation Collection. 2012.
[12] LS-DYNA. Theory Manual. Livermore Software Technology Corporation, CA, USA, 2006.
[13] S. E. Rigby, A. Tyas, T.Bennett, S. D. Clarke, and S. D. Fay. The negative phase of the blast load. International Journal of Protective Structures, 5(1):1–20, 2014.
[14] S. E. Rigby, A. Tyas, S. D. Fay, S. D. Clarke, and J. A. Warren. Validation of semi-empirical blast pressure predictions for far field explosions – is there inherent variability in blast wave parameters? In 6th International Conference on Protection of Structures against Hazards, Tianjin, China, 2014.
[15] W. E. Baker. Explosions in air. University of Texas Press, Austin, TX, USA, 1973.
[16] H. L. Brode. Numerical solutions of spherical blast waves. Journal of Applied physics, 26(6):766–775, 1955.
[17] E. L. Lee, H. C. Hornig, and J. W. Kury. Adiabatic expansion of high explosive detonation products. Technical Report TID 4500-UCRL 50422, Lawrence Radiation Laboratory, University of California, CA, USA, 1968.
[18] B. M. Dobratz and P. C. Crawford. LLNL explosives handbook - properties of chemical explosives and explosive simulants. Technical Report UCRL 52997, Lawrence Livermore National Laboratory, University of California, CA, USA, 1985.
[19] P.W. Sielicki. Masonry Failure under Unusual Impulse Loading. Publishing House of Poznan University of Technology, Poznan, 2013. ISBN 978-83-7775-274-6.
[20] A. Tyas, J. Warren, T. Bennett, and S. Fay. Prediction of clearing effects in far-field blast loading of finite targets. Shock Waves, 21(2):111–119, 2011.
[21] A. Tyas, T. Bennett, J. A Warren, S. D. Fay, and S. E. Rigby. Clearing of blast waves on finite-sized targets – an overlooked approach. Applied Mechanics and Materials, 82:669–674, 2011.
[22] S. E. Rigby. Blast Wave Clearing Effects on Finite-Sized Targets Subjected to Explosive Loads. PhD thesis, University of Sheffield, UK, 2014.
[23] S. E. Rigby, A. Tyas, S. D. Clarke, S. D. Fay, J. A. Warren, I. Elgy, and M. Gant. Testing apparatus for the spatial and temporal pressure measurements from near-field free air explosions. In 6th International Conference on Protection of Structures against Hazards, Tianjin, China, 2014.
